Elementary Algebra

by
Kaufmann, Jerome; Schwitters, Karen;

Answer

55-48i

Work Step by Step

We first use the FOIL method to simplify the expression. Then, knowing that $i=\sqrt{-1}$, we can substitute $-1$ for $i^{2}$ to obtain:
$(-3-8i)(3+8i)$
=$-3(3+8i)-8i(3+8i)$
=$-9-24i-24i-64i^{2}$
=$-9-48i-64i^{2}$
=$-9-48i-64(-1)$
=$-9+64-48i$
=$55-48i$